Engine ignition system

ABSTRACT

An ignition device for a turbine engine wherein said device has means for compressing air to a specified temperature and then directing said air into a combustion chamber. A predetermined metered amount of fuel in injected into the hot air so that auto ignition temperature is reached within the passageways of a catalytic restrictor-emitter. The flame started by the restrictor-emitter is held on its surface as a flame holder while the flame front projects into the combustion chamber to ignite a fuel/air mixture.

United States Patent [72] Inventor Raymond J. Bruchez, Jr.

Lake Park, Fla. [21 Appl. No. 846,833 [22] Filed Aug. 1, 1969 [45]Patented May 4, l 71 [73] Assignee United A rcraft Corporation EastHartford, Conn.

[54] ENGINE IGNITION SYSTEM 11 Claims, 2 Drawing Figs. [52] US. Cl60/39.82, 123/144, 431/268 [51] Int. Cl F021: 7/26 [50] Field of Search60/3982, 39.82(P), 39.06, 39.82(C); 123/144; 431/268(Inquired) [56]References Cited UNITED STATES PATENTS 799,856 9/1905 Lemale 60/39822,760,340 8/1956 Seglem 60/3982 2,920,445 1/1960 Bailey 60/39822,929,211 3/1960 Meyer 60/3982 3,355,885 12/1967 Toone 60/3982 FOREIGNPATENTS 612,060 11/1948 GreatBritain 60/3982 Primary Examiner-DouglasHart Att0rneyJack N. McCarthy rlNSULATlON I, -f5:'.- 241 a 57 /z 2/ i ZL5 I L5 44 5/; 57 42 54 Ei{8 VR id E a w 54 t 6 M M L-- START 4TSFIQGLET f PATENTED MAY 4 |97| COM PR EssoR comausnom SECTION EXHAUSTSECTION SECTION INSULATION INVENTOR. RAYMOND J. BRUCHEZJr ENGINEIGNITION SYSTEM BACKGROUND OF THE INVENTION In the ignition art forturbine engines two types appear to be the most closely related to thesubject device. One is the type of system that uses a pyrophoric fuel"and the second is a system in which a fuel is injected around a glowplug. However, subject ignition device differs basically therefrom. Apyrophoric ignition system is shown in U.S. Pat. No. 2,959,007 and anignition system using a glow plug is shown in U.S. Pat. No. 3,403,511.

SUMMARY OF THE INVENTION A primary object of the present invention is toprovide an igniter utilizing jet engine fuel and hydraulic pressure toproduce positive sustained directional emission. In accordance with thisinvention, a hydraulic actuator is connected to a double-acting pumpwhereby air is raised to a temperature adequate to accomplish autoignition with a catalyst. This invention also includes arestrictor-emitter which includes stacked screen-type layers ofplatinum-type material which acts as a catalyst with the heated air andpredetermined metered fuel which passes therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a gas turbineengine showing the location of an igniter as disclosed in thisapplication with respect to a combustion chamber.

FIG. 2 is an enlarged sectional view showing the igniter in detail.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a gasturbine power plant is shown indicated generally by I; the power planthaving a compressor section 2, a combustion section 4, a turbine section6, and an exhaust section 8. The combustion section 4 is comprisedhaving annular combustion chamber, or burner, positioned between thedownstream end of the compressor section and the entrance to the turbinesection. A power plant such as shown in FIG. 1 is disclosed more indetail in U.S. Pat. No. 3,980,176.

Air is directed to the burners 10 directly from the compressor sectionand fuel is injected into the chamber by fuel nozzles, not shown.Conventional gas turbine controls are used to obtain the desiredfuel-air mixture. To ignite the fuel-air mixture, an ignition device 12is provided. This ignition device 12 includes (1) a main igniter 14, (2)a control means 16, and (3) an injector 18.

The main igniter 14 includes two axially aligned cylinders 20 and 22.These cylinders are connected at their adjacent ends by a rigidinterconnecting member 24. Each cylinder, 20 and 22, has a pistonmember, 26 and 28, slideably mounted therein, respectively, for axialmovement. A rod 30 is connected to the face of each of the pistonmembers facing each other and extends through the member 24. Thisconnection coordinates the movement of the two piston members. Sealmeans 32 extends around the 'rod 30 adjacent cylinder 20 and seal means34 extends around the rod 30 adjacent cylinder 22.

Cylinder 20 has an opening 42 at its end adjacent to cylinder 22 and anopening 44 at is opposite end. Valve mechanism 46 cooperates withopening 42 to act as a check valve to only allow the fluid, air asshown, to flow from the cylinder 20. Valve mechanism 48 cooperates withopening 44 to act as a check valve to only allow the fluid to flow fromthe cylinder 20. A pressure reservoir 50 is positioned adjacent saidcylinder and is connected to the openings 42 and 44. An air admissionvalve 52 is located on the cylinder 20 at the center thereof. This valveis a one-way valve and only permits air to enter the cylinder 20.Conduit means 54 extends from the reservoir 50 and passes through thecasing of the engine 1 and through the wall of the combustion chamber 10to the interior thereof. A valve seat 56 is formed in conduit 54 and avalve member 58 is moveable into and out of cooperation with the valveseat 56 to start or stop the flow from the reservoir 50 through theconduit means 54.

A catalytic restrictor-emitter 60, part of the injector I8, ispositioned at the exit of said conduit means as it enters the combustionchamber. Valve member 58 is controlled by an actuating rod 62 whichextends into the control means 16. An ignition fuel injector 64, part ofthe injector 18, is located in said conduit means 54 to direct a fuelinto the restrictoremitter 60. A tube 66 interconnects the injector 64with the control means 16. The control means 16 opens valve member 58when desired and sends a predetermined metered amount of an ignitionfuel through tube 66 to the injector 64 at the same time to have properignition. This action occurs when the desired temperature or pressure inthe reservoir 50 is sensed by sensing device 57 and a signal is sent tothe control 16. The volume, V of the conduit means 54 between the valve58 and restrictor-emitter 60 is minimized in relation to the volume, Vof the reservoir 50, where, for example V could be one-tenth of VControl means 16 includes a source of fluid at actuating pressure and areservoir of fluid at low pressure. A control lever 40 is mechanicallyconnected to the control means 16 so that in its start position, asshown by solid lines in FIG. 2, with valve member 58 in the closedposition the control means 16 will direct fluid from the high-pressuresource to a first side of said piston member 28 while connecting theother side to the reservoir at low pressure. When the piston member 28reaches the end of cylinder 22 the control means 16 redirects the highpressure from the source to the other side of the piston member 28 andconnects the first side to the reservoir thereby reversing direction.This action is repeated until the temperature of the air in the pressurereservoir 50 is enough to start ignition.

This type of control is not new where a valve alternately connects ahigh-pressure source from one end of a cylinder to its other, whileconnecting the opposite end to a drain or a reservoir. Means fordetecting when the piston member 28 has reached either end of thecylinder can be a mechanical device actuated by the member such as shownat 37 and 39. Conduits 36 and 38 interconnect the control means 16 tothe opposite ends of the cylinder 22 for the flow of fluid just referredto.

In operation when the control lever 40 is moved to the start positionthe control means 16 supplies fluid to the cylinder 22 to move thepiston 28 therein from one end to the other until the piston 26 andcylinder 20 increases temperature in a reservoir 50 to a value which isadequate to accomplish auto ignition of a fuel in the restrictor-emitter60. The piston 26 draws air in through the valve 52 and, since the valve58 is being held in its closed position, forces the air through onecheck valve mechanism 46 and then the other check valve mechanism 48 toincrease the pressure and temperature in the reservoir 50.

When the desired temperature is reached in the reservoir 50, thetemperature sensor 57 sends a signal to the control means 16 which thenopens valve 58 and discharges a predetermined metered fuel charge intothe hot air as it enters the catalytic restrictor-emitter. Therestrictor-emitter is positioned between the reservoir and thecombustion chamber such that auto ignition temperature is reached withinthe passageways of the restrictor-emitter and the surface of the emitterfacing the combustion chamber acts as a holder for the flame front whichemits into the combustion chamber to ignite the fuel-air mixturetherein.

When ignition occurs, valve 58 has closed and the predetermined meteredfuel charge has been used. The control means 16 is reset to bereoperated for another ignition attempt, if necessary.

I claim:

1. In combination, an engine, said engine having a combustion chambertherein and an igniter, said igniter having means for compressing air toan elevated temperature, container means for holding said compressedair, first conduit means connecting said container means for holdingsaid compressed air to said combustion chamber, valved means forcontrolling the flow of compressed air from said container means to saidfirst conduit means, a catalytic'element in said first conduit meansdownstream of said valved means, a fuel supply, a second conduit meansconnecting said fuel supply to said first conduit means for injectingfuel into said first conduit means upstream of said catalytic element,control means for releasing compressed air from said container meansinto said first conduit means through said valved means and forreleasing fuel from said fuel supply into said first conduit meansthrough said second conduit means.

2. A combination as set forth in claim 1 wherein said means forreleasing fuel from said supply releases a metered charge of fuel.

3. A combination as set forth in claim 1 wherein said means forcompressing air comprises two cylinder and piston units, one cylinderand piston unit pumping said air into said container holding means forsaid compressed air, the second cylinder and piston unit being actuatedby fluid pressure directly on one side of piston and then on the otherafter it has moved a predetermined distance.

4. A combination as set forth in claim 1 wherein a sensing device ispositioned to sense a parameter of compressed air, said sensing devicebeing connected to said control means so that a signal is sent to saidcontrol means when said predetermined parameter has been reached andsaid control means then actuates said valved means releasing saidcompressed air to flow into said first conduit means and pass throughsaid catalytic element.

5. A combination as set forth in claim 3 wherein said one cylinder andpiston unit has an opening in each end which is connected to saidcontainer holding means for said compressed air, a check valve isconnected with each opening so that air is pumped from said cylinder andpiston unit into said container means for holding said compressed airand held there.

6. A combination as set forth in claim 1 wherein said means forcompressing air comprises two cylinder and piston units, one cylinderand piston unit pumping said air into said container means for holdingsaid compressed air, the second cylinder and piston unit being actuatedby fluid pressure directly on one side of piston and then on the otherafter it has vmoved a predetermined distance, the one cylinder andpiston unit has an opening in each end which is connected to saidcontainer means for holding said compressed air, a check valve isconnected with each opening so that air is pumped from said cylinder andpiston unit into said container means for holding said compressed airand held there.

7. A combination as set forth in claim 1 wherein said control means isresponsive to a sensing device which releasesthe compressed air when ithas reached a predetermined temperature.

8. A combination as set forth in claim 1 wherein said first conduitmeans is connected to said container means while its other end projectsinto said combustion chamber, said valved means being located where saidfirst conduit means is connected to said container means.

9. A combination as set forth in claim 1 wherein an injector is locatedin said first conduit means and connected to the second conduit means,said fuel being released through said injector.

10. A combination as set forth in claim 1 wherein said first conduitmeans forms a specific volume V between said valved means and saidcatalytic element, and said container means forms a specific volume Vthese volumes having a relationship of V,,=l/l0 V

1. In combination, an engine, said engine having a combustion chambertherein and an igniter, said igniter having means for compressing air toan elevated temperature, container means for holding said compressedair, first conduit means connecting said container means for holdingsaid compressed air to said combustion chamber, valved means forcontrolling the flow of compressed air from said container means to saidfirst conduit means, a catalytic element in said first conduit meansdownstream of said valved means, a fuel supply, a second conduit meansconnecting said fuel supply to said first conduit means for injectingfuel into said first conduit means upstream of said catalytic element,control means for releasing compressed air from said container meansinto said first conduit means through said valved means and forreleasing fuel from said fuel supply into said first conduit meansthrough said second conduit means.
 2. A combination as set forth inclaim 1 wherein said means for releasing fuel from said supply releasesa metered charge of fuel.
 3. A combination as set forth in claim 1wherein said means for compressing air comprises two cylinder and pistonunits, one cylinder and piston unit pumping said air into said containerholding means for said compressed air, the second cylinder and pistonunit being actuated by fluid pressure directly on one side of piston andthen on the other after it has moved a predetermined distance.
 4. Acombination as set forth in claim 1 wherein a sensing device ispositioned to sense a parameter of compressed air, said sensing devicebeing connected to said control means so that a signal is sent to saidcontrol means when said predetermined parameter has been reached andsaid control means then actuates said valved means releasing saidcompressed air to flow into said first conduit means and pass throughsaid catalytic element.
 5. A combination as set forth in claim 3 whereinsaid one cylinder and piston unit has an opening in each end which isconnected to said container holding means for said compressed air, acheck valve is connected with each opening so that air is pumped fromsaid cylinder and piston unit into said container means for holding saidcompressed air and held there.
 6. A combination as set forth in claim 1wherein said means for compressing air comprises two cylinder and pistonunits, one cylinder and piston unit pumping said air into said containermeans for holding said compressed air, the second cylinder and pistonunit being actuated by fluid pressure directly on one side of piston andthen on the other after it has moved a predetermined distance, the onecylinder and piston unit has an opening in each end which is connectedto said container means for holding said compressed air, a check valveis connected with each opening so that air is pumped from said cylinderand piston unit into said container means for holding said compressedair and held there.
 7. A combination as set forth in claim 1 whereinsaid control means is responsive to a sensing device which releases thecompressed air when it has reached a predetermined temperature.
 8. Acombination as set forth in claim 1 wherein said first conduit means isconnected to said container means while its other end projects into saidcombustion chamber, said valved means being located where said firstconduit means is connected to said container means.
 9. A combination asset forth in claim 1 wherein an injector is located in said firstconduit means and connected to the second conduit means, said fuel beingreleased through said injector.
 10. A combination as set forth in claim1 wherein said first conduit means forms a specific volume VE betweensaid valved means and said catalytic element, and said container meansforms a specific volume VR, these volumes having a relationship of VE1/10 VR.
 11. A combination as set forth in claim 1 wherein saidcatalytic element is a restrictor-emitter which will accomplish autoignition of a fuel therein with a flow of air passing therethrough whichis at an elevated temperature.